The present invention relates to a pin grid array (xe2x80x9cPGAxe2x80x9d) package socket for use in connecting a PGA package to a given electric circuit.
Conventional PGA sockets comprise a generally planar base housing having a plurality of terminals arranged in the form of grid, and a generally planar slide plate having a corresponding plurality of through holes arranged in the same form of grid as the generally planar base housing. The slide plate is placed on the base housing, and the base housing has a cylindrical cam member fitted on a pivot axle which passes through the slide plate, standing upright on the front end of the base housing, whereby clockwise or counterclockwise rotation of the cam member about its pivot axle makes the slide plate move back and forth between the opening position in which the lead pins of the PGA package can be inserted in the through holes to reach the terminal mounts and the locking position in which the inserted lead pins are put in engagement with the terminals.
It is necessary that the slide plate be closely laid on the base housing, not allowing the slide plate to come up whether it slides on the base housing or stays thereon. Referring to FIG. 10, in conventional PGA sockets, in order to assure that the slide plate 100 does not come up from the base housing 102 the slide plate 100 is designed to have hooks 101 formed on its opposite longitudinal sides to catch the opposite longitudinal sides of the underlying base housing 102 by snapping the slide plate 100 into its place. This rise-proof arrangement, however, requires application of a relatively strong force to the overlying slide plate. Apparently application of such a pushing force to the slide plate is disadvantageous to assembling work, and is one cause for lowering the assembling efficiency.
One object of the present invention is to provide a PGA package socket which does not require application of any force in fixing the slide plate to the base housing.
To attain this object, a conventional PGA package socket is improved according to the present invention in that the base housing has a traversal section formed in the vicinity of the pivot axle, thereby allowing the front end of the slide plate to be positioned under the traversal section while moving between the opening position and the locking position, thereby preventing the slide plate from coming up from the base housing.
With this arrangement the generally planar slide plate can be combined with the generally planar base housing simply by placing the slide plate on the base housing and by positioning the slide plate on the base housing until the forward end of the slide plate has been positioned under the traversal section of the base housing.
The cam member may have a radial retainer projecting from its lower part, and the base housing may have shoulders formed on the opposite sides of the pivot axle, thus limiting the rotation of the cam member to the range defined by the opposite shoulders.
The generally planar slide plate may additionally have a means for retaining the cam member to the pivot axle. One such means includes a resilient member engaging the radial retainer of the cam member appearing in the aperture through which the cam member passes, thereby retaining the cam member to the pivot axle.
The cam member may have a hook-ended axle formed at its center, and the cam member is rotatably fixed to the base housing with the hooks of the center axle being caught by the bottom of the base housing.
The base housing and slide plate may also have interengaging members for preventing the back end of the slide plate from coming up from the base housing.